Humans have never been a very sedentary species; instead, we have been moving always from one continent to another, across rivers, and across oceans. Geneticists are working with paleo-anthropologists together to piece together some of the stories of migrations that left no written record, because they took place long before anyone was writing.
The usual stories told of prehistoric migrations have an “out of Africa” theme. They discuss how various forms of hominid originated from the Mother Continent and migrated out of there, to the rest of the world.
But new research complicates that take considerably. It seems there was not merely a movement out of Africa, but some movement back. Apparently, people (homo sapiens sapiens for the most part though with some admixture of neanderthal in their genetic make-up) living somewhere in western Asia, migrated into Africa less than 200,000, but more than 140,000, years ago. There, they bred with gene-lines that had never left.
Strange New Worlds:
Genetic scientists use the word “haplotype” to refer to a group of genes within an organism that tends to be inherited together from a single parent. A Neanderthal-linked haplotype B006 has also been found among nomadic pastoral groups in the contemporary Sahel and the Horn of Africa, presumably among distant cousins of this back-migration.